If we relax "never" to "not more than 60 days a year", that would be most of Canada, northern US, most of Europe and Russia. No idea what's going on in southern hemisphere, but I guess Argentina/Chile and southern Australia are the same.

This obsession with mold looks to me as an exclusively US thing. I have no first-hand data but I guess it's due to insufficient air flow combined with air conditioners pushing humidity all the way up.